P3 Physics Work and Power

Work is done when a force moves an object in the direction in which the force acts.

Work done (J) = Energy Transferred (J)

Work done = Force x Distance Moved

Power

Power is the rate at which work is done.

Power = Work Done / Time Taken

A person's power is greater when they run than when they walk.

Power is also relate to force and speed.

= Power

= Work Done / Time Taken

= (Force x Distance) / Time Taken

= Force x (Distance / Time)

Force x Speed

Some cars are more powerful than others. They travel faster and cover the same distance in a shorter time and require more fuel. The power rating of a car depends on its engine size. More powerful cars have greater fuel consumption.

Fuel is expensive and a car with high fuel consumption is expensive to run.

Fuel pollutes the environment.

Car exhaust gases, especially carbon dioxide are harmful.

Carbon dioxide is also a major source of greenhouse gases, which contribute to climate change.

Weight

Weight is a measure of the gravitational attraction on a body acting towards the centre of the Earth.